Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible...
-
Upload
jasmine-henry -
Category
Documents
-
view
219 -
download
1
Transcript of Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible...
![Page 1: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/1.jpg)
Physics 301 AstronomyReview Slides
Fall 2012
![Page 2: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/2.jpg)
What is Different About Astronomy?
Incredible distances sizes periods of time
![Page 3: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/3.jpg)
![Page 4: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/4.jpg)
What is our place in the universe?
![Page 5: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/5.jpg)
Earth orbits the Sun (revolves) once every year:
• at an average distance of 1 AU ≈ 150 million km.• with Earth’s axis tilted by 23.5º (pointing to Polaris)• and rotating in the same direction it orbits, counter-
clockwise as viewed from above the North Pole.
![Page 6: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/6.jpg)
![Page 7: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/7.jpg)
We can recognize solstices and equinoxes by Sun’s path across sky:
Summer solstice: Highest path, rise and set at most extreme north of due east.
Winter solstice: Lowest path, rise and set at most extreme south of due east.
Equinoxes: Sun rises precisely due east and sets precisely due west.
![Page 8: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/8.jpg)
What determines the strength of gravity?
The Universal Law of Gravitation:1. Every mass attracts every other mass.2. Attraction is directly proportional to the product of
their masses.3. Attraction is inversely proportional to the square of
the distance between their centers.
![Page 9: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/9.jpg)
Conservation of Energy
• Energy can be neither created nor destroyed.
• It can change form or be exchanged between objects.
• The total energy content of the Universe was determined in the Big Bang and remains the same today.
![Page 10: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/10.jpg)
What does the solar system look like?
![Page 11: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/11.jpg)
Properties of Waves
• Wavelength is the distance between two wave peaks• Frequency is the number of times per second that a
wave vibrates up and down
wave speed = wavelength x frequency
![Page 12: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/12.jpg)
![Page 13: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/13.jpg)
What is the electromagnetic spectrum?
![Page 14: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/14.jpg)
Chemical Fingerprints
• Each type of atom has a unique spectral fingerprint
• Observing the fingerprints in a spectrum tells us which kinds of atoms are present
![Page 15: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/15.jpg)
Lines in a star’s spectrum correspond to a spectral type that reveals its temperature
(Hottest) O B A F G K M (Coolest)
![Page 16: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/16.jpg)
![Page 17: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/17.jpg)
Fission
Big nucleus splits into smaller pieces
(Nuclear power plants)
Fusion
Small nuclei stick together to make a bigger one
(Sun, stars)
![Page 18: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/18.jpg)
![Page 19: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/19.jpg)
Sunspots
Are cooler than other parts of the Sun’s surface (4000 K)
Are regions with strong magnetic fields
![Page 20: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/20.jpg)
The brightness of a star depends on both distance and luminosity
![Page 21: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/21.jpg)
Inverse Square Law for Light
Luminosity passing through each
sphere is the same
Area of sphere = 4π (radius)2
Divide luminosity by area to get
apparent brightness
Brightness is inversely proportional to the square of the distance from thr observor
luminosity
Apparent brightness = --------------------------
4 π x distance 2
![Page 22: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/22.jpg)
The relationship between apparent brightness and luminosity depends on distance:
Luminosity Brightness = 4π (distance)2
We can determine a star’s luminosity if we can measure its distance and apparent brightness:
Luminosity = 4π (distance)2 x (Brightness)
![Page 23: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/23.jpg)
Temperature
Lum
inos
ity
H-R diagram depicts:
Luminosity
Temperature
Color
Spectral type
Radius
![Page 24: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/24.jpg)
We see our galaxy edge-on.
Primary features: disk, bulge, halo, globular clusters
![Page 25: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/25.jpg)
Background radiation from the Big Bang
has been freely streaming across the universe
since atoms formed
at temperature ~3000 K: visible/IR.
BIG BANG
![Page 26: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/26.jpg)
VELOCITY
Velocity = (the speed) + (direction) of the motion of mass.
Expressed as a VECTOR QUANTITY
MAGNITUDE expressed as distance/time (10km/hr)
DIRECTION expressed in a direction (west)
30 km/hr
west
![Page 27: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/27.jpg)
Gravity is
a force of attraction
that exists
between any two masses,
any two bodies,
any two particles.
What is Gravity?
![Page 28: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/28.jpg)
What have we learned?• What is the Sun’s structure?
—From inside out, the layers are
• Core• Radiation zone• Convection zone• Photosphere• Chromosphere• Corona• Solar wind
![Page 29: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/29.jpg)
Most massive stars:
100MSun
Least massive stars:
0.08MSun
(MSun is the mass of the Sun.)
![Page 30: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/30.jpg)
What happens to a star is determined by the amount of mass a star has.
Low Mass (sun)
High mass (Betelgeuse)
![Page 31: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/31.jpg)
Some Other Stars on and Off the Main Sequence
![Page 32: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/32.jpg)
Hubble Classifies Galaxies
The Tuning Fork
![Page 33: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/33.jpg)
Three Basic Types of Galaxies
Spiral
Variations exist within these three types.
Elliptical
Irregular
![Page 34: Physics 301 Astronomy Review Slides Fall 2012. What is Different About Astronomy? Incredible distances sizes periods of time.](https://reader038.fdocuments.us/reader038/viewer/2022103004/56649c6f5503460f94921b8d/html5/thumbnails/34.jpg)